1. Field of the Invention
The present invention relates to a continuous vacuum batch type treating apparatus system for effecting a continuous plasma treatment under a vacuum on various plastic moldings such as plastic films, plastic sheets and plasticcoated electric wires.
2. Description of the Prior Art
A batch type treating system of the aforementioned type has been proposed which includes a vacuum treating chamber in which a soft article such as a plastic film is treated to improve its surface property.
A so-called air-to-air type treating system for a vacuum evaporation or ion plating on a hard material such as metallic tape, metallic wire or the like has been proposed, wherein the hard material is introduced from the atmospheric side into the vacuum treating chamber through a preparatory vacuum chamber disposed at the upstream side of the vacuum treating chamber and, after the formation of metallic or alloy film on the article, the article is conveyed to the atomspheric side through a post vacuum chamber. In this air-to-air type system, the vaccum is maintained in the preparatory vacuum chamber and the post vacuum chamber by means of a water seal or a nozzle seal.
In the first-mentioned system, i.e. the batch type system, it is comparatively easy to obtain the sealing means. However, after the improvement of the surface property of the article is achieved to some extent, it is necessary to break the vacuum in the vacuum chamber. Namely, a repeated build up and breakage of the vacuum is necessary for the treatment of successive batches of article. This not only hinders the in-line mass-production but also degrades the characteristics of the treated products.
More specifically, in the case of articles containing a volatile content such as a plasticizer, e.g. a resin film of vinyl cholride system, the property of the article will be degraded if the latter is left for a long time within a vacuum. It is, therefore, desirable to treat a batch of articles in quite a short period of time of the order of several tens of seconds. It is quite difficult to effect a treatment in such a short period of time within a vaccum treating chamber.
The second-mentioned type of system can easily apply to the treatment of hard articles because it is comparatively easy to obtain seals of preparatory vacuum chamber and post vacuum chamber without the fear of damaging of the surfaces of articles or cutting of the same. This air-to-air system, however, can hardly apply to treatment of soft articles because it is extremely difficult to achieve an effective seal for the preparatory vacuum chamber and the post vacuum chamber without fear of damaging or cutting of the article.